Medea is a play written by the Greek playwright Euripides. It is concerned with the opposition, the agon, between Greeks and barbarians, where the Greeks are rational, controlled people, and the barbarians are irrational, passionate, unthinking. In this way, the play confronts Greek ideas about nomos and physis.
The play deals with the later part of Jason's story, after he went and got the Golden Fleece. Jason and Medea had settled in the Greek city of Corinth, and when the play opens they have been living in Corinth for some time, long enough to have had two little boys, maybe six or seven years. At this point, the king of Corinth, Creon (KREE-on), asks Jason to marry his daughter, Creusa (kray-OO-sa). Creon has no sons, so if Jason marries Creusa he will be the next king of Corinth. Jason says yes, he will marry Creusa.
When Medea finds out that Jason is going to marry Creusa, she is very angry. After all she killed her brother to help Jason, and he carried her off from Colchis with him, and he has been living with her for years, and they have two children together. She thought they were married (the Greeks have no marriage ceremony). She tells Jason how angry she is, but he says well of course they were never married: how could he, a Greek, be married to a barbarian like Medea? Greeks only marry other Greeks.
Medea, he says, will have to leave Corinth, and she will have to leave their boys with him (fathers usually kept the children in a Greek divorce).
Medea gets even more angry than she was before. She makes a beautiful magic dress for Creusa, and sends her little boys to bring it to Creusa. When Creusa puts on the dress, though, it suddenly turns into fire and burns her up. Medea then kills her little boys, saying that if she can't have them, Jason can't either. Jason is very sad, and Medea leaves in a chariot drawn by dragons.
Bibliography and further reading about Medea and Euripides:
Greek Theatre, by Stewart Ross (1999). Easy reading.
Greek and Roman Theater, by Don Nardo. For teenagers.
Medea (Dover Thrift Editions) by Euripides. Translated by Rex Warner. The play itself, very very cheap.
Euripides (Oxford Readings in Classical Studies), by Judith Mossman (2003). A collection of essays by different people trying to explain what Euripides means. Good for college students, and maybe high school students too.
Medea, edited by James Clauss and Sarah Iles Johnston (1996). A collection of essays by specialists about the meaning of the myth of Medea.